CH431969A - Curable unsaturated polyester molding compounds stabilized by a content of copper complex compounds - Google Patents

Description

  

  
 



  Curable unsaturated polyester molding compounds stabilized by a content of copper complex compounds
Polyester molding compositions based on unsaturated polyesters and monomeric compounds which can be polymerized onto them tend to gel prematurely on storage, especially at elevated temperatures. It is known that the polyester molding compositions against this premature gelation by adding various inhibitors, for example phenols, such as hydroquinone, tert. Butylpyrocatechol and 4-ethylpyrocatechol, quinones, such as p-benzoquinone and 2, 5-di-tert. -butylbenzoquinone, certain aromatic amines, amine salts and quaternary phosphonium and arsonium salts.



   As is also already known, the stabilizing effect of the inhibitors mentioned is further improved or exceeded by soluble copper (II) compounds, especially copper salts of organic acids, such as copper (II) naphthenate. However, the copper (II) compounds have the disadvantage that they are intensely colored and, even in amounts which are in no way sufficient for effective stabilization of the polyester molding compositions, cause greenish-brown to greenish-blue discolouration of the molding compositions which are colorless per se.

   The discoloration of the molding compounds, which increases with increasing copper concentration, is already so strong at amounts of little more than one part of copper per 1 million parts of the molding compound that it is practically impossible to add even larger amounts of copper because of the intolerable discoloration associated with it
In order to avoid these disadvantages, it is obvious to replace the colored copper (II) compounds with colorless copper (I) compounds, such as copper (I) halides. However, it is difficult to distribute these compounds evenly in the molding compounds, since z.

   B. the copper (I) iodide is completely insoluble in it, while for copper (I) bromide and copper * (I) chloride larger amounts of solubilizers are required in order to dissolve sufficiently quickly and evenly in the oassen enable. However, the amounts of solubilizers required here, such as acetonitrile or dimethylformamide, are so great that they frequently impair the properties of the curing products produced from these molding compounds. It was also already. proposed to produce molding compositions containing copper (I) chloride by adding the copper (I) chloride to the starting materials for producing the unsaturated polyester before the polycondensation.

   Since, however, the copper (I) chloride is very unstable at the high reaction temperatures required for the polycondensation, it is easily oxidized to compounds of divalent copper in this procedure by oxidizing compounds, so that again discolored products are obtained.



   It has now been found that the disadvantages mentioned are avoided and barely colored polyester molding compositions containing excellent storage stability, soluble copper compounds as stabilizers are obtained if complex compounds of copper (I) chloride and / or copper (I) bromide are used to stabilize the molding compositions and neutral phosphoric acid esters are used.



   The complex compounds can be added to the polyester molding compositions directly at room temperature or at a moderately elevated temperature. They dissolve in the molding compositions without any particular difficulty and do not cause any disruptive discoloration even in comparatively large amounts. In general, for adequate stabilization, it is sufficient to add the copper compounds to the polyester molding compositions in such amounts that they contain up to about 50 parts of copper per 1 million parts of the molding composition.



   Examples of complex compounds to be used according to the invention are the complexes of copper (I) chloride and copper (I) bromide with triethyl phosphite, 2,2 ', 2 "trichloroethyl phosphite, tripropyl phosphite, triphenyl phosphite, etc., as described, for example, in Omeiin's Handbook of Inorganic Chemistry, System No. 60, Part B, Delivery 1, page 251 and page 365 are described.



   Unsaturated polyesters, whose solutions in monomeric, partially polymerizable compounds, can be stabilized according to the invention with advantage, are all unsaturated polyesters in the usual sense, in particular those with a content of α, ß-unsaturated dicarboxylic acids, optionally with a content of residues of other carboxylic acids and with a Content of, in particular, polyhydric alcohols.



   Examples of carboxylic acids suitable for the synthesis of polyester resins are:
Maleic acid, fumaric acid, itaconic acid,
Mesaconic acid, citraconic acid, succinic acid,
Glutaric acid, adipic acid, phthalic acid,
Tetrachlorophthalic acid, hexachloroendomethylene tetrahydrophthalic acid,
Trimellitic acid, benzoic acid, linseed oil fatty acid and
Ricinic fatty acid.



   Suitable alcohols are for example:
Ethylene glycol, diethylene glycol, propane, butane and hexanediol, trimethylolpropane,
Pentaeritrite, butanol and
Tetrahydrofurfuryl alcohol.



   According to the invention, for example, air-drying molding compositions which, in addition to the residues of a, ss-unsaturated dicarboxylic acids, also contain B, r-unsaturated ether residues, either as constituents of the polyester, for example according to German Auslegeschrift No. 1 024 654, can also be stabilized with advantage as a component of further mixture components, for example according to German Patent No. 1,067,210 and German Auslegeschrift No. 1 081 222, as well as unsaturated polyesters with a content of optionally condensed tertiary aromatic amines according to German Patent No. 919 431.



   Polymerisable monomeric compounds are the unge 5 aturated polymerisable compounds which are customary in polyester resin technology and have vinyl groups which are optionally substituted in the α-position or allyl groups which are substituted in the β-position, e.g. B. styrene, vinyl toluene, divinylbenzene, vinyl acetate, acrylic acid and their esters, acrylonitrile, methacrylic acid and their corresponding derivatives, and allyl esters, such as allyl acetate, allyl acrylate, diallyl phthalate, triallyl phosphate and triallyl cyanurate.



   The polyester molding compositions stabilized using the copper compounds according to the invention can also contain other conventional inhibitors.



   example 1
An unsaturated polyester with an acid number of 47, prepared by condensing 152 parts of maleic anhydride, 141 parts of phthalic anhydride and 195 parts of 1,2-propanediol and mixed with 0.045 parts of hydroquinone, is dissolved in 65% in styrene. Various samples of the polyester molding compound obtained are each adjusted to a copper content of 2 ppm by adding copper (II) naphthenate (sample A) or, according to the invention, [CuCl to P P (OC2H5) 5] (sample B).



  The properties of the molding compositions obtained are given in Table I below, together with the properties of the original polyester molding composition containing no copper (sample C).



   Table I.
A B C Color of the molding compound has a greenish discoloration colorless colorless Shelf life at 600 40 days 40 days 12 days Layer thickness 3 cm
Example 2
An unsaturated polyester with an acid number of 23 prepared by condensing 882 parts of maleic anhydride, 1332 parts of phthalic anhydride, 1098 parts of ethylene glycol and 963 parts of trimethylolpropandiallyl ether in the presence of 0.43 parts of hydroquinone is dissolved in 50% strength in styrene. Various samples of the polyester molding composition obtained are adjusted to a copper content of 20 ppm by adding copper (II) naphthenate (sample A) or, according to the invention, CuBr to P P (OCH5) 3] (sample B).

   The properties of the molding composition obtained are given in Table II below, together with the properties of the original polyester molding composition containing no copper (sample C).



   Table II
A B C Color of the molding compound * intense green discolored colorless colorless Shelf life at 800 7.5 days 7.5 days 2.5 days Layer thickness 3 cm
Example 3
According to Example 1 of German Patent No. 919 431, 73 parts of adipic acid, 98 parts of maleic anhydride, 74 parts of phthalic anhydride and 125 parts of glycol are condensed under customary conditions until 50% of the theoretical amount of water has distilled off. Then 7.5 parts of dioxyethylaniline are added and the mixture is condensed at 2000 until no more water passes over. The remaining water is distilled off in a vacuum at 15 mm and 2000. After cooling to 1600, 0.25 part of hydroquinone is added, and after further cooling to 1100, 140 parts of styrene are added.



   Various samples of the polyester molding composition obtained are each adjusted to a copper content of 25 ppm by adding copper (II) naphthenate (sample A) or, according to the invention, [CuCt P P (OCdJH9) 31 (sample B)). The properties of the molding compositions obtained are given in Table III together with the properties of the original, non-copper-containing polyester molding composition (sample C).



   Table III
A B c Color of the molding compound * intensive green discolored slightly yellowish slightly yellowish Shelf life at 1000 24 hours 27 hours 10 hours * Layer thickness 3 cm

 

Claims (1)

PATENT CLAIM Curable unsaturated polyester molding compositions stabilized by a content of copper compounds, characterized in that they contain complex compounds of copper (I) chloride and / or copper (I) bromide and neutral phosphorous acid esters as copper compounds.